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1
Woodburn, K. R., and J. R. Clark. "Cluster Modification Effects on the Performance of an Arkansas Table Grape Selection." HortScience 33, no. 4 (1998): 592b—592. http://dx.doi.org/10.21273/hortsci.33.4.592b.
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Flower cluster thinning effects were investigated on A-2274, a large-fruited, seedless table grape selection from the Univ. of Arkansas Grape Breeding Program. The objective of the study was to evaluate flower cluster thinning as a method to enhance cluster size and fill. Treatments included thinning to one flower cluster per shoot, removing one-half of each cluster, and a control (no flowers removed). Each treatment consisted of three, single-vine replications, with each vine being pruned to 32 buds. Removal of entire flower clusters (to one per shoot) resulted in larger clusters and a trend toward higher cluster fill ratings. Berry mass, number of clusters per vine, and yield per vine were unaffected by flower cluster treatment. Berries per cluster were reduced by the partial flower cluster removal treatment. Flower cluster thinning to one cluster proved a beneficial practice in increasing cluster characteristics of this promising selection.
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Kaps, Martin L., and Garth A. Cahoon. "Berry Thinning and Cluster Thinning Influence Vegetative Growth, Yield, Fruit Composition, and Net Photosynthesis of ‘Seyval blanc’ Grapes." Journal of the American Society for Horticultural Science 114, no. 1 (1989): 20–24. http://dx.doi.org/10.21273/jashs.114.1.20.
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Abstract Crop reduction on single-shoot ‘Seyval blanc’ grapevines by either berry or cluster thinning resulted in a decrease in total fruit weight and an accompanying increase in berry weight, °Brix, and vegetative growth. Titratable acidity and pH of the juice were not consistently affected by either berry or cluster thinning. Net leaf photosynthesis at 43 days past full bloom increased with higher cluster number per plant. Berry weight was greatest when the crop of berries were borne in three clusters per shoot rather than in a single cluster. Berry thinning appears to be an acceptable substitute to cluster thinning for crop reduction of ‘Seyval blanc’ grapes.
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Wilson, Patsy E., Douglas D. Archbold, Joseph G. Masabni, and S. Kaan Kurtural. "Cropload Management of ‘Vidal blanc’ Improves Primary Bud Cold Hardiness and Maintains Berry Composition in the Lower Midwestern United States." HortScience 49, no. 7 (2014): 874–80. http://dx.doi.org/10.21273/hortsci.49.7.874.
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Canopy architecture, yield components, berry composition, pruning weight, Ravaz Index, and midwinter primary bud cold hardiness of own-rooted ‘Vidal blanc’ (Vitis vinifera × Vitis rupestris) were measured in response to balanced pruning formula treatments of 20, 30, or 40 nodes retained for the first 454 g of dormant pruning weight and an additional 10 nodes for each additional 454 g and three cluster thinning levels of one, two, and two+ clusters per shoot in 2006 and 2007. Although the pruning formula affected the distance between shoots along the canopy, and the number of count shoots per hectare, the canopy leaf layer numbers were unaffected in either year. Application of the pruning formula did not affect components of yield in either year. However, the number of clusters and yield per vine were affected by cluster thinning treatments where they increased linearly with the decrease in its severity, explaining 73% and 77% of total variance in yield in 2006 and 2007, respectively. Pruning formula or cluster thinning did not affect berry composition substantially. Cluster thinning improved the percentage of mature nodes on shoots before a killing frost in both years. Cluster thinning to one or two clusters per shoot also improved the lethal temperature killing 50% of the primary buds compared with no cluster thinning in both years of the study. Mature wood weight and total pruning weight displayed a quadratic response to cluster thinning where two clusters per shoot had the greatest weight for both, whereas pruning formula had no effect on pruning weight. Optimum fruit weight–pruning weight ratio was achieved with the 30 + 10 pruning formula and two clusters per shoot cluster thinning treatments in both years of the study. The results of this study provide valuable information for growers of interspecific hybrids such as ‘Vidal blanc’ in the lower midwestern United States as well as in other regions with long, warm growing seasons. Balanced pruning to 30 nodes per 454 g of dormant prunings and cluster thinning to two clusters per shoots optimized yield, maintained fruit composition, improved primary bud cold hardiness, and achieved an optimum fruit weight-to-pruning weight ratio of 10.0 kg·kg–1. Thus, this approach should be used for ’Vidal blanc’ in the lower midwestern United States to sustain production.
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Striegler, R. Keith, and Vidal Perez-Munoz. "INITIAL EFFECT OF CROP CONTROL METHOD ON GROWTH, YIELD, AND FRUIT COMPOSITION OF ZINFANDEL GRAPEVINES IN CALIFORNIA." HortScience 27, no. 6 (1992): 600b—600. http://dx.doi.org/10.21273/hortsci.27.6.600b.
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Crop control methods were evaluated for two seasons in a commercial Zinfandel vineyard. The vineyard was trellised using a vertical two wire system and cane pruned. Vines were third-leaf when the experiment began. Treatments included control, cluster thinning, and shoot thinning. Cluster thinning consisted of removal of all clusters except the oasal cluster, while shoot thinning consisted of removal of 50% of shoots on canes. Treatments were imposed two weeks postbloom. Yield was not significantly affected by crop control method. Cluster thinning tended to increase berry weight and cluster weight. Crop control method had little effect on fruit composition. Vine growth, as indicated by dormant pruning weight, was not influenced by treatment in 1990 but showed a significant increase during 1991 for cluster-thinned vines. These results indicate little negative effect of high crop level on young Zinfandel vines when intensive management is practiced. Treatments will be monitored until equalibrium treatment effects are observed.
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Dami, Imed, Dave Ferree, Anton Prajitna, and Dave Scurlock. "A Five-year Study on the Effect of Cluster Thinning on Yield and Fruit Composition of `Chambourcin' Grapevines." HortScience 41, no. 3 (2006): 586–88. http://dx.doi.org/10.21273/hortsci.41.3.586.
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`Chambourcin' (Vitis sp.) is a French-American hybrid cultivar that has the propensity to overcrop, and its performance under cool climate and short growing season is not known. This study was conducted for five years (2000 to 2004) to evaluate the effect of three levels of cluster thinning (10, 20, and 30 clusters per vine) on yield and fruit composition of `Chambourcin' grown in northeastern Ohio. Cluster thinning reduced yield per vine and crop load, but increased pruning, cluster and berry weights. Cluster thinning also improved juice composition by increasing soluble solids and pH but not acidity. It was concluded that under the climatic conditions of this study, thinning to 10 clusters per vine (or 8 clusters per meter of row) produced the lowest yield but the highest vine size with the most optimum fruit composition. Therefore, vines from the 10-cluster treatment were considered the most balanced in the 5-year study. Additionally, due to the repeated coincidence of harvest with the first fall frost, it was suggested that the site in continental Northeast Ohio is risky for commercial production and longer and warmer seasons are thus preferred.
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Ivanišević, Dragoslav, Mladen Kalajdžić, Mato Drenjančević, Vladimir Puškaš, and Nada Korać. "The impact of cluster thinning and leaf removal timing on the grape quality and concentration of monomeric anthocyanins in Cabernet-Sauvignon and Probus (Vitis vinifera L.) wines." OENO One 54, no. 1 (2020): 63–74. http://dx.doi.org/10.20870/oeno-one.2020.54.1.2505.
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Aim: Leaf removal around clusters and cluster thinning are techniques usually applied in cool-climate vineyards in order to achieve optimal grape maturity. However, the impact of the timing of these two operations differs across varieties. Thus, the aim of the present work was to investigate the effects of cluster thinning and leaf removal timing (performed at three specific time points) on grape quality and monomeric anthocyanins in the wines of Cabernet-Sauvignon and Probus (Kadarka × Cabernet-Sauvignon, Vitis vinifera L.)Methods and results: The experiment was conducted in Sremski Karlovci (Northern Serbia) in 2014, 2015, and 2016. Leaf removal was applied on six basal nodes of each shoot at three time points, 7 days after flowering, 30 days after flowering, and at veraison, i.e., at the onset of berry ripening. After cluster thinning, which was performed 7 days after flowering, one cluster per shoot was retained. On the treated vines, leaf removal treatment and cluster thinning were applied only once. Leaf removal was more effective than cluster thinning in respect to grape quality. Leaf removal, applied 7 and 30 days after flowering, decreased titratable acidity in Cabernet-Sauvignon, while in Probus an interaction of leaf removal and year was observed. Moreover, early leaf removal decreased the incidence of Botrytis sp. in Probus. The varieties reacted differently to cluster thinning in respect to grape quality: cluster thinning increased total soluble solids in Probus and lowered titratable acidity in Cabernet-Sauvignon. In 2015, both cluster thinning and leaf removal yielded changes in the anthocyanin ratios in the wines. Cluster thinning increased total and acylated anthocyanins in the wine of Cabernet-Sauvignon compared to wine derived from unthinned vines. The peonidin content was 40 % higher in the Cabernet-Sauvignon wine if the vines were subjected to leaf removal treatments.Conclusions: Cluster thinning and leaf removal affected both Cabernet-Sauvignon and Probus (Vitis vinifera L.) grape quality and wine composition. Early leaf removal was the most effective treatment in both varieties. Therefore, combined application of cluster thinning and early leaf removal is highly recommended in the production of high-quality red wines in Serbia.Significance and impact of the study: Timing of leaf removal application was usually investigated around flowering and veraison. Our results suggested that leaf removal between these two phenological stages also improves grape quality and changes the ratio of the monomeric anthocyanins in the wine.
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Reynolds, Andrew G., Robert M. Pool, and Leonard R. Mattick. "Effect of Shoot Density and Crop Control on Growth, Yield, Fruit Composition, and Wine Quality of ‘Seyval blanc’ Grapes." Journal of the American Society for Horticultural Science 111, no. 1 (1986): 55–63. http://dx.doi.org/10.21273/jashs.111.1.55.
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Abstract A factorialized thinning level/shoot density experiment which was started in 1980 demonstrated that ‘Seyval blanc’ grapes benefits from cluster thinning in terms of vine size maintenance, cane ripening, berry weight, and Brix. Reducing shoot density led to increased cane ripening. Concomitant increases in cluster exposure improved fruit composition and led to higher berry weights. However, maintaining reasonably high shoot densities (4 shoots/30 cm of row or more) also was essential to maintain yield and vine size, even when crop was controlled by thinning. Levels of 4 shoots/30 cm of row and 17 clusters/500 g cane prunings are recommended to maximize yield and maintain reasonable fruit quality and vine size. Postbloom cluster thinning was found to reduce the incidence of bunch rot and to reduce the production of 2nd crop in 1982, without affecting any parameters of yield or fruit composition.
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Mu, Xinyang, Magni Hussain, Long He, et al. "An Advanced Robotic System for Precision Chemical Thinning of Apple Blossoms." Journal of the ASABE 66, no. 5 (2023): 1125–34. http://dx.doi.org/10.13031/ja.15678.
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Highlights A cartesian robotic spraying system was developed for precision apple blossom thinning. Flower clusters were detected and localized with deep learning model for target spraying. A communication algorithm was developed for positioning the spray end-effector to the target flowers. The cartesian robotic system greatly reduced chemical usage while maintaining thinning effectiveness in the final green fruit set. Abstract. Crop thinning, including blossom thinning, is one of the critical management strategies that determines the annual profitability of apple orchards. Challenges still remain for applying appropriate amounts of chemical thinner; if thinning is inadequate and too many fruits remain on the tree, fruit size will be small, fruit quality will be poor, and flower bud initiation for the following year’s crop may be either reduced or eliminated. Over-thinning also carries economic perils since yield and crop value in the year of application will be reduced. In addition, chemical thinning with excessive spray volume may cause leaf damage and fruit russeting. Thus, a robotic apple blossom thinning system was proposed, aiming to reduce the usage of chemical thinner while maintaining good thinning performance. The robotic system consisted of three major components: (1) a machine vision system that can identify and localize the apple flower clusters in tree canopies, (2) a cartesian robotic system with the guidance of a machine vision system to reach target flower clusters, and (3) a flat-shaped spraying nozzle connected with a solenoid valve as a spraying end-effector to deposit chemical thinner to the targeted flower clusters. A set of field tests was conducted to evaluate the performance of the robotic thinning system by comparing it to conventional air-blast and boom-type sprayers. In the test, the flower cluster detection reached a precision of 93.82%. The integrated robotic system used 2.3 L of chemical thinner to finish the chemical thinning for 18 apple trees, followed by the boom sprayer and air blast sprayer with 4.2 and 6.8 L usage, respectively. The robotic system also obtained an average fruit set of 2.4 per cluster after thinning, which was comparable to that of the air blast sprayer. The results showed that the robotic thinning system saved 66.7% and 45.5% of chemicals compared to the air-blast sprayer and boom-typed sprayers, respectively, while achieving a similar fruit set per cluster. The outcomes of the study provided guidance for developing a full-scale robotic chemical thinning system for modern apple orchards. Keywords: Apple orchard, Blossom thinning, Cartesian robot, Chemical thinning, Machine vision.
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Xu, Xiaoyu, Chifang Cheng, Xu Qian, Ying Shi, Changqing Duan, and Yibin Lan. "Influences of Cluster Thinning on Fatty Acids and Green Leaf Volatiles in the Production of Cabernet Sauvignon Grapes and Wines in the Northwest of China." Plants 13, no. 9 (2024): 1225. http://dx.doi.org/10.3390/plants13091225.
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Cluster thinning has been widely applied in yield management and its effect on green leaf volatiles (GLVs) in wines has seldom been studied. GLVs are important flavor compositions for grapes and wines. This work aimed to investigate the impact of cluster thinning on these volatiles and their precursors in grapes and wines. Severe cluster thinning (CT1) and medium cluster thinning (CT2) were performed on Cabernet Sauvignon (Vitis vinifera L.) vines in two sites (G-farm and Y-farm) from Xinjiang province in the Northwest of China. The impact of cluster thinning treatments on the accumulation of GLVs and their precursors, long chain fatty acids (LCFAs) of grape berries and C6 volatiles, in resulting wines was investigated. Multivariate analysis showed that cluster thinning treatments induced significant changes in fruit and wine composition in both farms. In Y-farm, medium cluster thinning (CT2) significantly increased the average cluster weight of harvested berries. Additionally, both cluster thinning treatments (CT1 and CT2) increased fatty acids in harvested berries and CT2 led to an increase in C6 esters and a decrease in C6 alcohols in the wines of Y-farm under the warmer and drier 2012 vintage. However, the effect of cluster thinning was likely negative in G-farm due to its wetter soil and excessive organic matter. The treatments may be applicable for local grape growers to improve viticultural practices for the more balanced vegetative and reproductive growth of Cabernet Sauvignon grapevines. This work also provided further knowledge on the regulation of fatty acids and the derived C6 volatiles through the lipoxygenase (LOX) pathway.
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Kurtural, S. Kaan, Imed E. Dami, and Bradley H. Taylor. "Effects of Pruning and Cluster Thinning on Yield and Fruit Composition of `Chambourcin' Grapevines." HortTechnology 16, no. 2 (2006): 233–40. http://dx.doi.org/10.21273/horttech.16.2.0233.
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Response of yield components and fruit composition of `Chambourcin' (Vitis vinifera × V. rupestris) grapevines to three pruning levels of 15, 20, and 25 nodes retained for each pound of dormant prunings; and three cluster thinning levels of 1, 2, and 2+ clusters per shoot in 2002 and 1, 1.2, and 1.5 clusters per shoot in 2003 were measured at two vineyards in the lower midwestern United States. In both years of the study, there was very little interaction of pruning and cluster thinning. The proportion of non-count shoots increased within the canopy in response to increased pruning severity. Pruning weight means were lower in 2002 across all treatments compared to 2003. Pruning weights decreased with the increase in the number of clusters retained per vine. Pruning influenced yield only in 2003 when the proportion of count shoots decreased below 62% of the total, hence the relationship between number of shoots per vine and yield (R2 = 0.3452; P < 0.0003). In both years of the study, the increase in severity of cluster thinning resulted in yield reduction but an increase in the total soluble solids in juice. Yield compensation was achieved by an increase in cluster weight of 38%, and 25% in response to a reduction of 37%, and 23% in cluster numbers; which translated into a yield reduction of only 10% and 3%, at Vineyards 1 and 2, respectively. Balanced pruning to 15 to 20 nodes per 1 lb of prunings and cluster thinning to 1 to 1.2 clusters/shoot optimized yield (9.7 kg/vine, 13.4 t·ha-1) and fruit composition, and maintained vine size (≥0.3 kg·m-1 of row). These results provide valuable information for growers of `Chambourcin' grapevines in the lower midwestern U.S., as well as in other climates with long growing seasons.
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Peña-Neira, A., A. Cáceres, and C. Pastenes. "Low Molecular Weight Phenolic and Anthocyanin Composition of Grape Skins from cv. Syrah (Vitis vinifera L.) in the Maipo Valley (Chile): Effect of Clusters Thinning and Vineyard Yield." Food Science and Technology International 13, no. 2 (2007): 153–58. http://dx.doi.org/10.1177/1082013207077920.
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Changes in phenolic composition were determined in cv. Syrah-vines grape skins during ripening for two contrasting yields, resulting from cluster thinning at veraison. Treatments consisted on 16 and eight clusters per plant leading to approximately 8 ton/ha (T1) and 4 ton/ha (T2). In the grape skins of the samples analysed, 11 different low molecular weight phenolic compounds were identified, as well as 15 anthocyanins. Cluster thinning had a minimal effect on ripening time and weight of grape skins, however, clusters from low yield plants resulted in a lower total acidity and slightly higher pH. As for the phenylpropanoid pathway, the flavan-3-ol (+)-catechin, and the flavanols isorhamnetin-3- O-galactoside and isorhamnetin-3- O-glucoside, resulted in a higher concentration in berry skins from low yield plants. It is concluded that cluster thinning may result, from the oenological point of view, in an increased grape quality especially in compounds related to wine colour.
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Reynolds, Andrew G. "‘Riesling’ Grapes Respond to Cluster Thinning and Shoot Density Manipulation." Journal of the American Society for Horticultural Science 114, no. 3 (1989): 364–68. http://dx.doi.org/10.21273/jashs.114.3.364.
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Abstract Five-year-old ‘Riesling’ grape (Vitis vinifera) vines growing in the Okanagan Valley of British Columbia were subjected to three crop levels (full crop, two clusters per shoot, and one cluster per shoot) in combination with no shoot thinning or thinning to 24 shoots per meter of row. Reduction in crop level improved vine size and cane periderm formation slightly. Yield per vine was linearly related to crop level, but berry weight, berries per cluster, and cluster weight increased with decreasing crop level. °Brix and pH increased and titratable acidity decreased with reduction in crop level. Thinning to 24 shoots per meter of row provided some improvement in yield components and °Brix. Crop loads below 10 kg of fruit per kilogram of cane prunings are necessary to achieve adequate fruit maturity under Okanagan conditions.
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Nordi, Nicholas Taborda, Luciano Rodrigues Coelho, Sarita Leonel, et al. "Yield and Fruit Quality of Loquat Trees as a Result of Flower Bud Thinning." Horticulturae 11, no. 3 (2025): 270. https://doi.org/10.3390/horticulturae11030270.
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The size and appearance of loquats are crucial for their acceptance in the consumer market. The loquat tree has intense fruiting, which suggests thinning flower buds in order to improve the quality of loquat fruit production. This study was performed in the Paraíba Valley region of the state of São Paulo, in the subtropical region of southeastern Brazil to assess intensities of flower thinning at full bloom on the yield and fruit quality of loquat trees. The study was carried out over two consecutive harvest seasons. Trees of the cultivar ‘Precoce de Itaquera’ were used in a randomized block design with five intensities of hand thinning of the flower buds (4, 6, 8, 10, and 12 buds per cluster), with seven replicates. For all treatments, the clusters were bagged as soon as they were thinned. After harvesting, the number of fruit sets, cluster and fruit mass, yield, longitudinal and transverse lengths, number and mass of seeds, soluble solids content, titratable acidity, ripeness index, and pH of the fruit pulp were assessed. An overall improvement was achieved by maintaining four flower buds per cluster. This intensity of thinning provides greater fruit setting on the cluster, as well as larger and sweeter fruit. The highest cluster weight and yield were obtained by maintaining 12 flower buds per cluster.
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Gao, Yu, and G. A. Cahoon. "FRUIT CLUSTER THINNING, SHADIHG, AND DEFOLIATION ON FRUIT COLOR DEVELOPMENT OF RELIANCE GRAPES." HortScience 27, no. 6 (1992): 600a—600. http://dx.doi.org/10.21273/hortsci.27.6.600a.
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Significant differences in fruit color were created with fruit cluster thinning (20, 40, and 60 clusters/vine), cluster shading (full sun as control, 55% shading, and 95% shading using shading cage constructed of shade cloth), and defoliation (3, 6, 9, 12, and 15 leaves/cluster). Fruit cluster shading and defoliation treatments decreased red fruit color (characterized by Hunte Color a). Fruit cluster thinning increased red fruit color. Anthocyanin profile of Reliance grape was characterized as cyaninidin-3-glucoside and delphinidin-3-glucoside using Paper Chromatography and Thin Layer Chromatography. Analyses of total anthocyanin content (pH shift method), individual anthocyanin and soluble carbohydrates content (High Performance Liquid Chromatography), are being conducted to determine effects of carbohydrate allocation to fruit and sun light on fruit color of Reliance grapes.
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Tahmaz, Hande. "Changes in physical and chemical characteristics of Syrah grapes in response to timing of cluster thinning." Acta Scientiarum Polonorum Hortorum Cultus 22, no. 5 (2023): 63–71. http://dx.doi.org/10.24326/asphc.2023.5014.
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Cluster thinning was performed on vines of the Syrah variety eight days before the véraison (CTBV) and after the completion of the véraison (CTAV) in the 2019 and 2021 vegetation periods. The differences in physiological and chemical properties between the grapes were investigated to which cluster thinning was applied at two different times and those without cluster thinning. According to the research results, CTBV was more effective in the berry fresh weight, dry weight, berry volume, skin weight, skin surface, cluster width, cluster length, cluster weight, and cluster volume parameters than CTAV. Likewise, the levels of total phenolic compounds, total anthocyanins, and antioxidant capacity increased by 9%, 27%, and 30%, respectively, compared to the control group without cluster thinning. Among the phenolic compounds, trans-resveratrol showed the highest increase of 38%, and petunidin-3-glucoside increased the most (12%) among anthocyanins.
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REYNOLDS, ANDREW G. "IMPACT OF PRUNING STRATEGY, CLUSTER THINNING, AND SHOOT REMOVAL ON GROWTH, YIELD, AND FRUIT COMPOSITION OF LOW-VIGOR DE CHAUNAC VINES." Canadian Journal of Plant Science 69, no. 1 (1989): 269–75. http://dx.doi.org/10.4141/cjps89-036.
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To explore alternative means of crop control on vineyard attributes, 10-yr-old, low-vigor De Chaunac vines were subjected over a 3-yr period to eight crop regulation treatments, which involved combinations of pruning strategy (15 + 10 balanced pruning; 40 nodes per vine), cluster thinning, shoot thinning to one shoot per node, and removal of base shoots. Treatments involving cluster thinning maximized vine size, periderm development, yield components, °Brix, and anthocyanins. Yield per vine was not affected by any treatment. Cane periderm, yield components, and °Brix of cluster thinned, balance pruned vines exceeded those in cluster thinned vines pruned to 40 nodes. Shoot thinning of balance pruned vines did not improve cane periderm formation or yield components over un-thinned vines, but reduced °Brix. Combining cluster and shoot thinning with balanced pruning and base shoot removal proved to be superior to all treatments in every aspect of growth, yield, and fruit composition. Vines pruned to 40 nodes and subjected to base shoot removal and shoot thinning had improved yield components and °Brix over vines shoot thinned only, but were inferior to cluster thinned vines in terms of all vineyard parameters. Crop loads below 7 kg kg−1 cane prunings appear necessary to maintain vine size, yield, and acceptable fruit composition of low-vigor De Chaunac vines.Key words: Vitis, De Chaunac, pruning, cluster thinning, vine
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Rehman, Noor, Asif Latif, Malik Muhammad Hashim, et al. "Fruit Thinning Enhances Yield and Quality of Local Apple Fruit (Malus domestica Borkhausen) var. Gaja in Pakistan." Philippine Agricultural Scientist 103, no. 1 (2020): 66–72. https://doi.org/10.62550/db30049019.
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The apple tree usually has heavy fruit set but to improve the individual fruit size, apple growers reduce the number of fruits by thinning. The present study was carried out to assess yield and quality of apple fruit as influenced by fruit thinning. The experiment was carried out in a randomized complete block design (RCBD), with two factors, viz. time of thinning (factor 1) and amount of thinning (factor 2). Factor 1 included thinning after 2 wk of fruit set and 4 wk after fruit set; Factor 2 included one fruit per cluster, two fruits per cluster, three fruits per cluster, and four fruits per cluster. Each treatment was replicated three times. The indigenous apple germplasm Gaja was selected for the experiment. Fruit diameter, fruit length, fruit weight, fruit color, total soluble solids (TSS), and fruit pH were significantly improved by fruit thinning intensity while total yield, fruit drop percent, number of fruits per kg and fruit firmness were reduced by increasing thinning intensity. Leaving 2–3 fruits per cluster not only improved the fruit size (diameter and length) but also gave maximum economic return.
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Janás, Martin, Lucia Benešová, Štefan Ailer, and Mária Levická. "Utilization of different yield regulation methods of the vine for production of wines of higher designation protected of origin." Potravinarstvo Slovak Journal of Food Sciences 17 (March 23, 2023): 231–41. http://dx.doi.org/10.5219/1877.
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Grape yield regulation is a method used to improve grape quality parameters. Experiments were carried out in 2021 on the grapevine (Vitis vinifera L.) wine varieties 'Feteasca regala' and 'Sauvignon blanc', focusing on the effect of two different methods of grape yield regulation on its selected parameters and must sugar content. The first method used was cluster thinning, leaving one bunch on the shoot. The next method used was cluster tipping when we removed the terminal part of each bunch. Yield reduction was carried out in the period between pea-sized berry phenophase (BBCH 75) and bunch closure phenophase (BBCH 77). The operations were carried out manually. Cluster thinning did not lead to a statistically significant difference in bunch weight compared to the control in any of the studied varieties. We observed a statistically significant (p <0.05) decrease in the average bunch weight in the variant cluster tipping. The 'Feteasca regala' hectare yield was 32.25% lower in the cluster thinning than the control. The hectare yield in the cluster thinning variant was reduced by 46.61% compared with the control. Cluster thinning variant of the Sauvignon blanc variety had a 19.13% lower yield than the control variant. The cluster tipping variant had a 29.03% lower yield than the control variant. In the case of the cluster thinning method, we observed a greater decrease in grape yield compared to the cluster tipping method. The obtained results indicate that cluster tipping method is preferable to the cluster thinning in terms of the profitability of grape production. The must sugar content was statistically significantly (p <0.05) increased in all the yield reduction variants. The variety 'Feteasca regala' had the highest sugar content of the must in the cluster thinning method, 19.42 kg/hL. The highest sugar content of 'Sauvignon blanc' was 21.33 kg/hL in the variant with cluster tipping. This shows that regulating the grape yield can improve the quality parameters of the grapes. On the other hand, it may lead to a decrease in yield per hectare below the break-even point. The justness and intensity of the method used must be carefully considered.
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Esperanza Valdés, María, Daniel Moreno, Esther Gamero, et al. "Effects of cluster thinning and irrigation amount on water relations, growth, yield and fruit and wine composition of Tempranillo grapes in Extemadura (Spain)." OENO One 43, no. 2 (2009): 67. http://dx.doi.org/10.20870/oeno-one.2009.43.2.799.
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<p style="text-align: justify;"><strong>Aim</strong>: The effects of cluster thinning and irrigation regime on vine performance and grape and wine quality of Tempranillo grapevines were studied in a field experiment carried out in Extremadura in Spain.</p><p style="text-align: justify;"><strong>Methods and results</strong>: Treatments were combinations of two irrigation doses (25% and 100% of estimated crop evapotranspiration) and two crop levels (thinned and unthinned vines). Cluster thinning was performed just before veraison to retain five clusters per m2 of vine leaf area. Results showed that irrigation amount produced important differences in stem water potential, leaf area index and berry growth but cluster thinning did not significantly affect these parameters. However, cluster thinning independently of the irrigation amount, advanced by seven days grape maturity and largely affected the main grape quality parameters, increasing total soluble solids concentration, pH, total anthocyanins and phenolic content and reduced must yield. Wines made from grapes of the thinned treatments also had higher contents of anthocyanins, tanins and colour index. This increasing effect was more noticeable in the lower irrigation dose. Similarly, the higher irrigation amount reduced phenolic content of wines.</p><p style="text-align: justify;"><strong>Conclusion</strong>: Both, lower irrigation rates and cluster thinning, despite decreased yield, improved wine composition. Overall thinning had a larger impact on grape and wine composition than irrigation.</p><p style="text-align: justify;"><strong>Significance and impact of study</strong>: In the semi-arid environment of the Extremadura region of Spain, irrigation in Tempranillo is important to obtain economically sound yield. However, the irrigation dose to apply might vary depending on the desired wine style. Irrigation to replace potential evapotranspiration should be avoided for premium wine production and, in these cases; deficit irrigation is probably preferred as a tool to increase yields but minimizing the negative effects on fruit and wine quality. Cluster thinning, performed just before veraison, can be also applied to accelerate ripening improving the overall fruit phenolic composition.</p>
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Hannam, K. D., G. H. Neilsen, D. Neilsen, and P. Bowen. "Cluster thinning as a tool to hasten ripening of wine grapes in the Okanagan Valley, British Columbia." Canadian Journal of Plant Science 95, no. 1 (2015): 103–13. http://dx.doi.org/10.4141/cjps2013-397.
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Hannam, K. D., Neilsen, G. H., Neilsen, D. and Bowen, P. 2015. Cluster thinning as a tool to hasten ripening of wine grapes in the Okanagan Valley, British Columbia. Can. J. Plant Sci. 95: 103–113. Achieving fruit maturity can be a challenge on some Okanagan vineyards in some years. Cluster thinning is widely used to hasten ripening, but may not be effective on sites with balanced crop loads. In a Merlot vineyard in Summerland, BC, the effects of cluster thinning on juice soluble solids (an indicator of fruit maturity), yield and vine growth were examined between 2008 and 2011 across a range of treatments that manipulated the frequency and quantity of applied irrigation water. Cluster thinning increased juice soluble solids in 2 out of 3 study years and consistently increased cluster weights, but had few effects on juice pH, titratable acidity or yield. In 2 of 3 yr, correlation analyses showed that cluster thinning was most effective at improving the maturity of fruit with low soluble solids. Irrigation treatments did not have a consistent effect on juice composition but year-to-year variability was significant. Response ratios calculated from values reported in the literature show that cluster thinning in this region causes small but inconsistent improvements in juice soluble solids across a range of crop loads.
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Yue, Xiaofeng, Yanlun Ju, Yulin Fang, and Zhenwen Zhang. "Transcriptomics Integrated with Metabolomics Reveals the Effect of Cluster Thinning on Monoterpene Biosynthesis in ‘Muscat Hamburg’ Grape." Foods 10, no. 11 (2021): 2718. http://dx.doi.org/10.3390/foods10112718.
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Monoterpenes are crucial to floral and fruit aromas in grapes and wines. Cluster thinning is a common practice for improving grape quality. Using Vitis vinifera cv. Muscat Hamburg, the effects of three cluster-thinning regimes on the biosynthesis and accumulation of monoterpenes from véraison to harvest were investigated at the transcriptomics and targeted metabolomics levels. It was observed that more intense thinning produced higher concentrations of total monoterpenes, particularly in their bound forms. The numbers of differentially expressed genes among the three treatments were 193, 200, and 238 at the three developmental stages. In total, 10 modules were identified from a weighted gene correlation network analysis, and one module including 492 unigenes was associated with monoterpene metabolism. These findings provide new insights into the molecular basis of the relationship between cluster thinning and monoterpene biosynthesis in Muscat Hamburg grape. Cluster thinning could be carefully considered for its application in production.
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Lu, Xiang Yang, Li Ming Zhang, and Yong Huang. "Shear Thinning and Thickening of Alumina Suspensions." Advanced Materials Research 105-106 (April 2010): 833–36. http://dx.doi.org/10.4028/www.scientific.net/amr.105-106.833.
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The rheological behavior of alumina suspension stabilized with Tri-ammonia citrate (TAC) was studied. It was thought that there would form some particle clusters due to the collisions between particles caused by their relative motion in the suspension, and such particle clusters are classified as thermodynamic clusters and hydrodynamic clusters by their origin. Shear thinning is the result of decomposition of the thermodynamic clusters, while shear thickening is the result of formation of the hydrodynamic clusters. From the view of cluster-forming potential barrier, it was deemed that the viscosities of alumina suspensions at low and high shear rates are respectively determined by zeta potential and Stern potential on the particle surface, and shear thickening behavior can be suppressed with some excessive TAC.
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Mucalo, Ana, Irena Budić-Leto, Katarina Lukšić, Edi Maletić, and Goran Zdunić. "Early Defoliation Techniques Enhance Yield Components, Grape and Wine Composition of cv. Trnjak (Vitis vinifera L.) in Dalmatian Hinterland Wine Region." Plants 10, no. 3 (2021): 551. http://dx.doi.org/10.3390/plants10030551.
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Defoliation and cluster thinning are of practical importance in a control of the grapevine source-sink balance, cluster architecture, microclimate and berry composition. Nevertheless, their effectiveness on wine composition is unexplored. In this work, the impacts of preflowering (T1), after berry set (T2), and veraison defoliation (T3) and cluster thinning (T4), on yield components, grape and wine composition of cv. Trnjak are given. Implemented techniques significantly reduced yield and affected grape and wine components in comparison to untreated control (C). Despite lowest number of clusters ensured by cluster thinning, defoliation at veraison had lowest yield. Defoliations improved cluster architecture parameters. Highest berry per se was in preflowering T1 and lowest at veraison T3 defoliation. Berries of T1 had lowest sugar content (19.47 °Brix) while T3 had highest (22.3 °Brix), and the reverse is seen in total acidity highest in T1 (6.12 g/L) and lowest in T3 (5.01 g/L). Wines of early defoliations (T1 and T2) had lowest alcohol and highest anthocyanin concentration. Both techniques applied at veraison produced wines with lower anthocyanins and flavonols than those obtained without any intervention (C). In conclusion, the early defoliations (T1 and T2) improve yield and wine composition of cv. Trnjak in the Mediterranean region of Croatia.
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Doğan, Osman. "Determination of Effects of Some Summer Pruning Applications on Yield and Quality Characteristics of Alphonse Lavallée (Vitis vinifera L.) Grape Variety." Horticulturae 11, no. 4 (2025): 445. https://doi.org/10.3390/horticulturae11040445.
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Grapes, one of the most delicious and refreshing fruits in the world, are a source of sugar, minerals, and vitamins. Summer pruning affects ripening, disease control, yield, and quality parameters by controlling the vine microclimate. In our study, leaf removal, fruit thinning, and cluster thinning and their combination were applied to the Alphonse Lavallée grape variety, aiming to improve yield, cluster, and berry characteristics. As a result of the applications, cluster and berry characteristics, SSC, pH, titratable acidity (TA), total phenolic content, antioxidant activity, and color parameters were examined. In our study, all summer pruning applications and their combinations caused increases in cluster and berry parameters (weight, length, and width) compared to the control. In addition to these, the SSC, pH, and maturity index increased and TA decreased. All these applications also increased berry detachment and skin rupture force, which have an important place in road resistance in table grape varieties. Significant improvements were also seen in the quality parameters of total phenolic content and antioxidant activity. In addition, there were increases in the lightness and chroma values that determine the fruit quality in table grapes. Considering all these data, the summer pruning applications we made had significant effects on yield and quality. It is thought that cutting a part of the clusters instead of the whole cluster will especially prevent the yield loss experienced in cluster thinning applications.
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Alshallash, Khalid S., Moustafa A. Fahmy, Anas M. Tawfeeq, et al. "GA3 and Hand Thinning Improves Physical, Chemical Characteristics, Yield and Decrease Bunch Compactness of Sultanina Grapevines (Vitis vinifera L.)." Horticulturae 9, no. 2 (2023): 160. http://dx.doi.org/10.3390/horticulturae9020160.
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Nowadays, the Sultanina grapevines H4 strain has become widely cultivated because of its high productivity. However, this Sultanina variety is suffering from clusters with small berries, in addition highly compacted berries, thus negatively affecting the quality of bunch berries. A field experiment was carried out during the two successive seasons on Five years old Sultanina (H4 strain) grapevines grafted onto freedom rootstock grown in a private orchard located in El-Khatatba region, Minufyia Governorate, with coordinates of 30°21′ N 30°49′ E. The investigation was designed to throw light on the effect of hand thinning at levels 0, 25%, and or 50% of cluster shoulders was removed in addition to spray with 0, 20, 30, and 40 ppm GA3 for berry sizing. In addation, the first application was the hand thinning treatment, which was used on the second and third week of May for the first and the second seasons. The second application was the berry sizing treatment, applied when the berries were at 6–7 mm diameter (on the 3rd and 4th week of May for the first and the second seasons. Results indicated that the total chlorophyll content of leaf decreases when the hand thinning levels or GA3 concentration increases, while hand thinning and GA3 treatments were higher than control only concerning pruning weight. Moreover, the results showed that the first level of hand thinning treatments recorded higher values for the cluster weight than the higher level of hand thinning treatments with all the concentrations of GA3 used for sizing. The highest value was with T2. The overperformance of T2 for the vine yield and the rest of the treatments at the lower level of hand thinning were better than those at the higher level of hand thinning. In conclusion, hand thinning at 50% level and sizing with GA3 at concentration 30 ppm reduced the cluster compactness and improved the berry weight and firmness. Therefore, it could be recommended to get the most suitable yield and quality of Sultanina grapevines.
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Choi, Sujung, Seunghyun Ban, and Cheol Choi. "The Impact of Plant Growth Regulators and Floral Cluster Thinning on the Fruit Quality of ‘Shine Muscat’ Grape." Horticulturae 9, no. 3 (2023): 392. http://dx.doi.org/10.3390/horticulturae9030392.
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Plant growth regulators (PGRs) and floral cluster thinning are commonly used to improve grape yield and quality, but their effects on different fruit quality attributes in the ‘Shine Muscat’ are not well understood. In this study, we investigated the impact of PGRs and floral cluster thinning on various fruit quality parameters such as the cluster weight, berry weight, diameter, shape, sugar and acid content, firmness, and residual feel of peel. Our results indicate that the gibberellic acid 3 (GA3) 25 mg/L + thidiazuron (TDZ) 5 mg/L treatment at full bloom and GA3 25 mg/L treatment at 12 days after full bloom showed the largest cluster weight, berry weight, and diameter, while the forchlorfenuron (CPPU)-treated group, with a more balanced effect on fruit skin and flesh firmness, had the highest proportion of a positive residual feel of the peel. Floral cluster thinning by 4 cm was found to be effective for promoting fruit growth and maintaining an appropriate sugar–acid ratio, while thinning by 5 cm resulted in a higher number of berries but smaller berry size and lower sugar–acid ratio. These findings can be useful for grape growers and researchers in optimizing PGR and floral cluster thinning treatments to improve grape yield and quality.
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Hampson, Cheryl, and Karen Bedford. "Efficacy of blossom thinning treatments to reduce fruit set and increase fruit size of Ambrosia and Aurora Golden Gala™ apples." Canadian Journal of Plant Science 91, no. 6 (2011): 983–90. http://dx.doi.org/10.4141/cjps2011-070.
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Hampson, C. and Bedford, K. 2011. Efficacy of blossom thinning treatments to reduce fruit set and increase fruit size of Ambrosia and Aurora Golden Gala™ apples. Can. J. Plant Sci. 91: 983–990. The usefulness of several blossom thinning treatments to reduce fruit set and improve the final fruit size of two new Canadian apple (Malus×domestica Borkh.) cultivars was investigated. Ambrosia and 8S6923 (also called Aurora Golden Gala™) apple trees in a high density commercial superspindle planting were used. Ammonium thiosulphate (ATS) at 1.6% vol/vol or Crocker's fish oil and lime sulphur (FOLS) at 2+2% vol/vol were applied at 20 and 80% full bloom with an airblast sprayer. The chemical blossom thinning treatments were compared with a positive control [hand blossom thinning (HBT)], done at open cluster to king bloom stage, and a negative control (no blossom thinning). All trees received follow-up hand thinning as necessary to end up with a commercial crop load (single fruits about 15 cm apart). Hand blossom thinning resulted in about 95% single-fruit clusters and obviated the need for further thinning, but required considerable labour. Both ATS and FOLS reduced initial set (fruit number per tree, mean fruit number per cluster), but neither eliminated the need for follow-up fruitlet thinning. The two chemicals had similar efficacy in many respects, but FOLS was superior in certain specific measures of performance. In 2009, ATS negatively altered the fruit size distribution for 8S6923. For 8S6923, HBT improved fruit size without reducing yield. Ambrosia fruit size was less responsive to blossom thinning, and in the second year, yield was lower for trees receiving HBT. No fruit russet occurred on either cultivar. Return bloom was sufficient for a full crop for both cultivars after both years. 8S6923 was more productive than Ambrosia but was more difficult to thin.
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Zabadal, Thomas J., and Thomas W. Dittmer. "QUANTITATIVE MEASUREMENT OF CLUSTER COMPACTNESS IN SEVERAL TABLE GRAPE CULTIVARS." HortScience 27, no. 6 (1992): 599g—600. http://dx.doi.org/10.21273/hortsci.27.6.599g.
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Cluster compactness can affect fruit quality by influencing pesticide spray penetration into clusters and by predisposing berries to cracking and subsequent decay. Compactness of clusters can be altered through gibberellic acid sprays, flower cluster thinning and pruning severity. Assessment of cluster compactness has often been performed using a visual rating system which may not provide adequate quantitative measurement. Evaluation of cluster compactness by insertion of wedges between randomly chosen pairs of berries on a cluster revealed a high correlation with a visual rating system and a more sensitive measure of cluster compactness than the visual rating system. Several pruning severity treatments were applied to table grape cultivars to determine their influence on cluster compactness. It was possible to measure statistically significant differences in cluster compactness among these treatment using this wedge measurement technique.
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Rohla, Charles T., Michael W. Smith, and Niels O. Maness. "Influence of Cluster Thinning on Return Bloom, Nut Quality, and Concentrations of Potassium, Nitrogen, and Non-structural Carbohydrates." Journal of the American Society for Horticultural Science 132, no. 2 (2007): 158–65. http://dx.doi.org/10.21273/jashs.132.2.158.
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Alternate bearing pecan trees [Carya illinoinensis (Wangenh.) C. Koch] were hand-thinned annually to 1, ≤2, or ≤3 fruit/cluster or not thinned when the ovule was about one-half expanded. Return bloom was monitored on (1) vegetative shoots, (2) bearing shoots without a second growth flush in the terminal position on 1-year-old branches, (3) bearing shoots without a second growth flush in the lateral position on 1-year-old branches, and (4) bearing shoots with a second growth flush that were primarily in the terminal position. Yield and nut quality were determined in addition to nonstructural carbohydrate, organically bound nitrogen (N), and potassium (K) concentrations in the roots and shoots during January. Fruit thinning improved return bloom but had little effect on weight/nut, kernel percent, or kernel grade. Fruit thinning had either a modest or no effect on nonstructural carbohydrates, organically bound N, and K concentrations. Vegetative shoots and bearing terminal shoots produced a similar number of flowers/1-year-old branch and percentage of flowering current-season shoots. Bearing lateral shoots produced fewer flowers than vegetative shoots most years and fewer flowering current-season shoots during one year. Shoots with a second growth flush produced more flowers/1-year-old branch and a larger percentage of flowering current-season shoots than did vegetative shoots 2 of 3 years. These data indicate fruit thinning of overloaded trees improved return bloom, but the lack of interactions between thinning treatment and shoot type suggests that the number of fruit/cluster was less important than total crop load in determining nut quality and return bloom. Thus removal of entire fruit clusters appears as effective as thinning fruit within a cluster to maintain adequate nut quality and promote return bloom. Nonstructural carbohydrates, organically bound N, and K were not limiting factors in bearing consistency because they were not depressed in unthinned trees. Nonstructural carbohydrates, organically bound N, and K concentrations were not closely linked to alternate bearing because return bloom was enhanced by thinning, but thinning did not affect their concentrations.
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Chen, Zezhun, and Angelos Dassios. "Cluster point processes and Poisson thinning INARMA." Stochastic Processes and their Applications 147 (May 2022): 456–80. http://dx.doi.org/10.1016/j.spa.2022.02.002.
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Ferree, David C., Garth A. Cahoon, David M. Scurlock, and Maurus V. Brown. "Effect of Time of Cluster Thinning Grapevines." Small Fruits Review 2, no. 1 (2003): 3–14. http://dx.doi.org/10.1300/j301v02n01_02.
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Gil-Muñoz, Rocío, Rosario Vila-López, José Ignacio Fernández-Fernández, and Adrián Martínez-Cutillas. "Effects of cluster thinning on anthocyanin extractability and chromatic parameters of Syrah and Tempranillo grapes and wines." OENO One 43, no. 1 (2009): 45. http://dx.doi.org/10.20870/oeno-one.2009.43.1.786.
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<p style="text-align: justify;"><strong>Aims</strong>: The effects of cluster thinning on yield and extractability parameters of Syrah and Tempranillo grapes, as well as the chromatic characteristics of the wines obtained in three consecutive seasons.</p><p style="text-align: justify;"><strong>Methods and results</strong>: Grapes of Vitis vinifera L. var. Tempranillo and Syrah were harvested from a commercial vineyard in Jumilla. Two treatments were evaluated: (a) cluster thinned, where in every shoot all the clusters, except the basal one, were removed just before veraison; (b) unthinned control. Yield, physicochemical and extractability parameters were studied in the grapes. Vinifications were made from these grapes, and chromatic parameters were studied at the end of alcoholic fermentation. Results showed that cluster-thinned vines performed better than control vines during the three consecutive years of the experiment, although the best results were obtained in the driest year (2005). The Syrah variety always provided better results than the Tempranillo variety. The cluster-thinning treatment also influenced the chromatic characteristics of the wines obtained.</p><p style="text-align: justify;"><strong>Conclusions</strong>: The results showed that thinning successfully reduced yield and produced an earlier harvest in the two varieties studied. The grape quality improved and, in general, wines made from cluster-thinned vines of both Syrah and Tempranillo had significantly better chromatic characteristics than control wines.</p><p style="text-align: justify;"><strong>Significance and impact of the study</strong>: This study demonstrate that the practice of cluster-thinning may be recommended depending on several factors, as the varieties and the climatic conditions play also a role in the extractability parameters of grapes, and therefore its use cannot be generalized.</p>
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Netsawang, Prud, Lutz Damerow, Peter Schulze Lammers, Achim Kunz, and Michael Blanke. "Alternative Approaches to Chemical Thinning for Regulating Crop Load and Alternate Bearing in Apple." Agronomy 13, no. 1 (2022): 112. http://dx.doi.org/10.3390/agronomy13010112.
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In the past, chemical thinning dominated in fruit orchards. This paper for the special issue outlines alternatives to chemical thinning for crop load management (CLM) and its effect on fruit size, firmness, sugar, starch, and weight, indicating ripeness and fruit quality, yield, and alternate bearing. A total of 450 apple trees (Malus domestica Borkh., cv. ‘Roter Boskoop’; six years old) on M9 rootstock were used at the Klein-Altendorf experimental station (50° N) of the University of Bonn, Germany. As the first alternatives, trees were mechanically blossom-thinned at the balloon stage (BBCH 59) with a rotor speed of 320 rpm or 380 rpm at 5 km/h tractor speed or were chemically thinned at the full bloom stage (BBCH 65) with ammonium thiosulfate (ATS), ethephon (ETH), and/or 6-benzyladenine (BA) at 10–12 mm fruit size (BBCH 71) after applying ATS/ETH. Flower clusters and/or cluster leaves (source) were manually removed to determine the optimum sink-source ratio to achieve different ratios of fruitlets (sink) relative to the leaves (source) at fruit set (BBCH 67–69). Un-thinned, adjacent trees served as the control. The majority of CLM methods improved fruit size and weight. Removing cluster leaves at fruit set increased fruit size and weight of the remaining fruit, which has not been observed before. The most effective treatment for fruit size and weight and return bloom was the 75% flower cluster and complete cluster leaf removal. Removal of more than 50% of flower clusters successfully improved return bloom, indicative of alternate bearing. The mechanical blossom thinning had a positive effect on fruit size and weight with a return bloom similar to that of removal of 50% flower clusters.
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Artem, Victoria, and Arina Oana Antoce. "Enhancement Of Cabernet Sauvignon Wine Volatile Profile By Organic Cultivation Confirmed With An Electronic Nose." “Agriculture for Life, Life for Agriculture” Conference Proceedings 1, no. 1 (2018): 244–49. http://dx.doi.org/10.2478/alife-2018-0036.
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Abstract Cabernet Sauvignon is one of the grape varieties highly suitable for organic cultivation. In the present study, the variety was cultivated in Murfatlar region were both organic and conventional technologies are applied and compared. Also, for each growth system variants with and without 30% cluster thinning were organized. Wines obtained from each variant were compared by the use of an electronic nose. The groups of wines prepared by the same technology were discriminated by the electronic nose in accordance to their volatile profile and on the basis of the discriminating chromatographic peaks determined. The wines produced from grapes conventionally grown were discriminated in two groups by different compounds correlated to the application or not of the cluster thinning operation, while the wines from organic grapes were only slightly separated in groups with or without cluster thinning. However, the wines from organic grapes have shown the highest complexity, as far as the number of discriminant peaks is concerned. Thus, this preliminary study suggests that organic cultivation of grapes may be beneficial for Cabernet Sauvignon wines. The operation of cluster thinning has some effects on the wines made with conventionally grown grapes, but even in this case only 7.6% of the variability in the volatile profile is explained by the cluster thinning. Considering that the grape yield of Cabernet Sauvignon is generally low as compared to other varieties, a further reduction of the grape load may be economically unjustified.
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Obradović, Valentina, Brankica Svitlica, Maja Ergović Ravančić, Svjetlana Škrabal, Helena Marčetić, and Josip Mesić. "Utjecaj prorjeđivanja grozdova na kakvoću mošta kultivara Chardonnay u kutjevačkom vinogorju." Agronomski glasnik 82, no. 4 (2021): 173–84. http://dx.doi.org/10.33128/ag.82.4.2.
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Kutjevo wine-hills are located on southern slopes of Papuk and Krndija mountains. The area is the most famous by production of Graševina grapes, but increasing share of other varieties cannot be ignored. Chardonnay is the most widespread variety all over the world, and in Požeško-slavonska county is represented by 5 % of total vineyards area. The aim of this research was to determine the influence of cluster thinning in Kutjevo wine-hills on maturation and must quality of Chardonnay grapes. Research was conducted in 2020 in Podgorje location (Kutjevo wine-hills). Experiment was established by a randomized block schedule in two treatments with three repetitions. Five vines in a row makes one repetition. The following parameters have been determined: sugar content and total acidity in grapes in period of one month before harvest, number of clusters per vine, cluster mass, mass of 100 berries, density, total acidity, volatile acidity, tartaric acid, malic acid, lactic acid, pH, reducing sugars, extract, glucose, fructose, glycerol, alfa amino nitrogen, ammonia nitrogen and potassium. Results have showed that cluster thinning had a significant influence on cluster mass and number of clusters per vine, but majority of chemical parameters were not significantly different between two treatments. Statistically significant difference was only in case of pH, lactic acid and ammonium nitrogen
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Mucalo, Ana, Katarina Lukšić, Irena Budić-Leto, and Goran Zdunić. "Cluster Thinning Improves Aroma Complexity of White Maraština (Vitis vinifera L.) Wines Compared to Defoliation under Mediterranean Climate." Applied Sciences 12, no. 14 (2022): 7327. http://dx.doi.org/10.3390/app12147327.
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Defoliation and cluster thinning are useful canopy management techniques to modulate grapevine carbon distribution and microclimate. Both techniques are directed to achieve the proper balance between fruit and foliage, and to maximize production of well-ripened fruits and quality wines. We performed five canopy treatments on Maraština grapevine grown at a commercial vineyard in the Vrgorac Valley region of Croatia: three different times of basal defoliation, cluster thinning at the veraison, and an untreated control. The effects of the canopy changes on the chemical composition of grapes and wines were studied. The treatments had variable impacts on yield components and basic wine composition. Volatile aroma compounds in produced wines were analyzed using gas chromatography–mass spectrometry coupled with a mass-selective detector. The concentrations of 70 of the 96 individual volatile compounds were significantly influenced by the canopy technique used. The concentrations of 58 of these compounds were different according the timing of defoliation. Cluster thinning at an intensity of 35% produced wines with more terpenes, esters, higher alcohols, other alcohols, volatile phenolic compounds, lactones, and other compounds than other treatments. Among terpenes, cluster thinning increased terpinen-4-ol, linalool, trans-β-farnesen, and geraniol. Odor activity value analysis revealed 16 volatile compounds that contributed to the aroma of cluster-thinned wines.
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Bound, Sally A. "Crop Load Management in Nashi Pear—A Review." Horticulturae 8, no. 10 (2022): 923. http://dx.doi.org/10.3390/horticulturae8100923.
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Most nashi cultivars require heavy thinning, and this has traditionally been performed by the time and labour-intensive practice of hand thinning. Crop load management is a key cost driver for nashi production, but there are limited cost-effective options available for nashi growers compared to other pome fruit, especially apples and, to a lesser extent, European pears. There is, however, potential to adapt some of the thinning tools and techniques used in apples and European pears to reduce the labour requirements and high cost of thinning in nashi, thus improving industry profitability. Several chemical thinning agents have potential for nashi, and an understanding of the optimal application rates, times and weather conditions for each chemical, as well as the conditions/factors that impact the tree carbon balance, will improve the predictability of chemical thinning. However, it is difficult to target specific flowers/fruitlets within a cluster with chemicals, and the flowers that produce the preferred fruit shape and size are in the middle of the flower cluster. Mechanical thinning during the flowering period with either Darwin or BAUM-style string thinners has potential, particularly as these devices can be used as early as flower emergence. As for chemical thinning, the issue of non-selectivity needs to be addressed; however, the development of mechatronic systems should overcome most problems that occur with the currently available mechanical thinners. Shading at critical times is an avenue that could be explored further to ascertain the critical stage when developing fruit are susceptible to enable the determination of the optimal timing and duration of shading. Targeted pruning and bud thinning during the dormant winter period to reduce the floral bud numbers is a valuable option for the precise placement of fruit in optimal positions and to set up the required number of clusters. This review highlighted several tools/techniques that, with further work, can be incorporated into a systematic approach to crop load management in nashi while reducing the risk and cost.
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Fitzgerald, John, and W. Keith Patterson. "Response of `Reliance' Table Grapes to Canopy Management and Ethephon Application." Journal of the American Society for Horticultural Science 119, no. 5 (1994): 893–98. http://dx.doi.org/10.21273/jashs.119.5.893.
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Canopy management and ethephon application (100 mg·liter-1 2 weeks after veraison) were investigated for 2 years as possible ways to improve color and overall quality of `Reliance' grapes (Vitis spp.). Canopy management consisted of leaf removal, shoot positioning, and cluster thinning. Grapevines were subjected to one of two levels of leaf removal and one of two levels of preharvest ethephon spray and were either thinned to a basal cluster or nonthinned. Thinning and ethephon advanced harvest dates by 5 to 8 days and 2 to 3 days, respectively. In 1989, berry weight was increased by thinning but was not affected by leaf removal or ethephon. Leaf removal (direct sun exposure) of thinned and nonthinned treatments increased “L” values (lighter colored fruit) in 1989. In 1990, leaf removal, ethephon, and thinning resulted in higher “L” values. The “a” values were significantly increased by leaf removal in 1989 and 1990 and by thinning in 1989, a result indicating increased skin redness. Exposed clusters of nonthinned treatments had significantly higher “b” values due to more yellow fruit in 1989 than in 1990. Ethephon increased “b” values in thinned and nonthinned treatments. In 1990, leaf removal increased “b” values. Thinning resulted in more evenly colored, redder fruit. Leaf removal caused a lightening and yellowing of the skin. Juice from leaf removal treatments in 1990 had significantly higher “L”, “a”, and “b” values. Ethephon significantly increased the “a” value of juice in 1989, and leaf removal significantly increased the “b” value in 1989. The percent soluble solids of juice was generally decreased by ethephon and increased by leaf removal and thinning. Titratable acidity was decreased by leaf removal and ethephon and increased by thinning in both years. Leaf removal decreased berry pH in 1990. Thinning increased coloration, and direct exposure to light decreased coloration. The results with ethephon were not conclusive. Chemical name used: 2-chloro-ethyl-phosphonic acid (ethephon).
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Nedelkovski, Dushko, Venelin Roychev, Klime Beleski, and Todorka Mokreva. "The Effects of the Summer Pruning Operations on the Winter Buds Productivity of cv. Vranec (Vitis vinifera L.)." АГРОЗНАЊЕ 18, no. 3 (2018): 155. http://dx.doi.org/10.7251/agren1703155n.
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The study presents the analysis of the influence of summer pruning operations (defoliation, cluster thinning) on the parameters of a potential productivity of winter buds at the vine variety Vranec grown near Veles in the period 2013-2015. For this research, four treatments were set: control, defoliation and two types of cluster thinning: 10 and 6 clusters per vine. From the obtained results it is found that there are no injuries in the main winter buds during the vegetation period and the potential fruitfulness is determined by higher coefficient, 1.38, which depends on the location along the cane. The yield at this variety will be formed mainly by clusters with size of 350-550 μm, followed by those with the length of 550-750 μm. The application of defoliation and regulation of the vine yield has a beneficial effect on increasing the rate of potential fruitfulness of winter buds, the number of buds with 2 and 3 clusters, increasing the inflorescences with a length of 350-550 μm and the appearance of those longer than 750 μm.
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Zhuang, Shijian, Letizia Tozzini, Alan Green, et al. "Impact of Cluster Thinning and Basal Leaf Removal on Fruit Quality of Cabernet Franc (Vitis vinifera L.) Grapevines Grown in Cool Climate Conditions." HortScience 49, no. 6 (2014): 750–56. http://dx.doi.org/10.21273/hortsci.49.6.750.
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Achieving desired fruit quality at harvest in cool climate conditions is a challenge, especially for red varieties, and the typical inability of fruit to reach technological maturity is a critical contributing factor requiring examination. To probe this issue, this research investigated the impact of two levels of crop thinning and of basal leaf removal at three phenological stages in the 2011 and 2012 growing seasons in Michigan. Experiments were conducted at the Southwest Michigan Research and Extension Center (SWMREC) in Benton Harbor. Using ‘Cabernet franc’ (Vitis vinifera L.) vines, yield components (yield per vine, pruning weight, and cluster and berry weight) and basic fruit composition traits [total soluble solids (TSS), pH, titratable acidity, anthocyanins, and phenolics) were studied to investigate the effect of cluster thinning and basal leaf removal on vine performance and fruit quality at harvest. Neither of the treatments significantly impacted TSS in either of the two seasons. Cluster thinning treatment successfully altered cropload ratio, indexed as Ravaz Index (RI), independently of the time of application. Basal leaf removal increased exposed berry temperature, cluster light exposure, and subsequent anthocyanin and phenolic content of the berry in both seasons, again independent of application date, whereas cluster thinning was effective only in 2012. Crop thinning coupled with basal leaf removal resulted in an increased efficiency in anthocyanin accumulation in relation to TSS accumulation, expressed as anthocyanin:sugar, in both years. This is significant because it offers potential for vineyard management practices aiming to improve fruit quality in cool climates where the onset of anthocyanin accumulation could be reduced and decoupled from sugar accumulation.
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Miranda, Carlos, Luis G. Santesteban, and José B. Royo. "Influence of Reproductive Impairment of Most Developed Flowers on Fruit Set and Fruit Quality in Pear." HortScience 40, no. 5 (2005): 1276–79. http://dx.doi.org/10.21273/hortsci.40.5.1276.
Full textAbstract:
The lowest flower in the pear (Pyrus communis L.) cluster usually develops and blooms first and also has a greater sink potential. For this reason, resources are preferentially utilized by the lowest fruit, and this is also one of the reasons why most thinning practices tend to favor their set. However, it is not always possible to perform selective thinning. This study was undertaken to determine if hindering pollination in the most developed flowers in the cluster influences yield or quality compared to that obtained in a whole open-pollinated cluster. The treatments were made in `Blanquilla' (Spadona, Agua de Aranjuez) and `Conference' pear within a wide range of flower densities for each cultivar. Pollination was hindered by cutting off the flower styles. The factor tested was style removal intensity (SRI). Treatments consisted in removing the styles of two, four(always the most developed), or all flowers in each cluster. Flower density was used as a covariate in an analysis of covariance to account for differences in flower densities in response to SRI treatments. In all experiments the covariate was not significant; therefore, SRI effect was not affected by flower density. `Blanquilla' and `Conference' had similar responses to treatments, so that when at least three flowers are susceptible to be openly pollinated, fruit set, seed content, and cluster yield were similar to control clusters, therefore the growth potential of fruit from partially damaged clusters in their most developed flowers is similar to undamaged open pollinated clusters. The reduced set of parthenocarpic clusters implies yield reductions ranging between 40% and 60% in `Conference', and up to about 60% in `Blanquilla'.
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Mota, Renata Vieira da, Claudia Rita de Souza, Camila Pinheiro Carvalho Silva, et al. "Biochemical and agronomical responses of grapevines to alteration of source-sink ratio by cluster thinning and shoot trimming." Bragantia 69, no. 1 (2010): 17–25. http://dx.doi.org/10.1590/s0006-87052010000100004.
Full textAbstract:
The control of leaf to fruit ratio by the practice of entire clusters removal from the vine upon berry set has been used in traditional vineyards in order to regulate yield and to improve chemical composition of the berries. Although this practice has been settled in temperate zones, little is known about grapevines behavior in tropical growing areas. The aim of this work was to evaluate the biochemical and agronomical responses of two Vitis vinifera cultivars (Merlot and Cabernet Sauvignon) grown in Caldas, Minas Gerais, Brazil, a new winegrape region. Grapevines were submitted to cluster thinning (0%, 50% and 75% of cluster removal) and trimming treatments (trimmed and untrimmed) imposed at pea size stage. The source-sink alteration by fruit removal and shoot trimming had impact on yield, leaf sugar metabolism and grape composition. Although there was an improvement in color intensity of the berries with reduction of fruit load, the cluster thinning practice should be avoided in vineyards grown in the south of Minas Gerais State without impairment of wine grape quality. On the other hand, shoot trimming practice should be recommended only for Merlot in order to improve sugar grapes from vines with no cluster removal.
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Shikhamany, S. D., Swapnil V. Borade, Sanjay K. Jeughale, and Suryakant Y. Patil. "Effect of Cane Regulation and GA3 Spray on Berry Thinning in 'Thompson Seedless' Grape (Vitis vinifera L.)." Journal of Horticultural Sciences 11, no. 2 (2016): 131–42. http://dx.doi.org/10.24154/jhs.v11i2.83.
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A field trial was conducted during 2013-14 and 2014-15 fruiting seasons in growers' vineyards around Nashik, Maharashtra, India to improve efficacy of GA3 sprays in berrythinning. As smaller clusters have fewer berries, cluster compactness derived at by number of berries per unit length (cm) of rachis, and, berry-diameter were considered as a measure of berry-thinning. As GA3 effect in berry-thinning is stage-specific, canes uniformly thick in a vine only were retained to achieve uniformity in flowering, by inducing uniform bud-break. Cane regulation did not result in uniformity in bud-break or flowering. Blanket spray of GA3 thrice @ 20g a.i./ha, each coupled with either removal of non-uniform canes or retention of all the canes could effectively reduce cluster compactness by reducing number of berries per cluster, without increasing total length of the rachis/cluster or berry diameter. Vine yield and quality in terms of total soluble solids and acid content were not affected by the treatments. Considering cluster-compactness, yield and ease of cultural operations, retention of all the canes in a vine, coupled with three blanket sprays each of GA3 @ 20g a.i/ha, on alternate days commencing from initiation of the bloom, is recommended for 'Thompson Seedless'.
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Mawdsley, Paul, Jean Dodson Peterson, and L. Casassa. "Agronomical and Chemical Effects of the Timing of Cluster Thinning on Pinot Noir (Clone 115) Grapes and Wines." Fermentation 4, no. 3 (2018): 60. http://dx.doi.org/10.3390/fermentation4030060.
Full textAbstract:
A two-year study was performed to evaluate the effects of the timing of cluster thinning on Pinot noir grapes and wines in the central coast of California. Vines were thinned to one cluster per shoot at three selected time-points during the growing season, and fruit was harvested and made into wine. No consistent effect of cluster thinning was found in wine phenolic profile or color across a cool (2016) and a warm (2017) growing season. The growing season had a more significant effect than the cluster thinning treatment for most parameters measured. There was no detectable overall sensory difference between the non-thinned control wines and any of the thinned treatment wines. Based on current results, Pinot noir vineyards on the central coast of California can support crop loads that result in Ravaz Index values from 3 to 6 without concern for impacting ripening potential or negatively affecting fruit composition.
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Karoglan, M., M. Osrečak, L. Maslov, and B. Kozina. "Effect of cluster and berry thinning on Merlot and Cabernet Sauvignon wines composition." Czech Journal of Food Sciences 32, No. 5 (2014): 470–76. http://dx.doi.org/10.17221/598/2013-cjfs.
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The manipulation of grape yield is widely practised to improve grape and wine quality. Merlot and Cabernet Sauvignon vines in the Zagreb vineyard hills, north-western Croatia, were subjected to three crop removal treatments [cluster thinning (CT), berry thinning (BT), CT+BT, and untreated control] in a randomised block design experiment. CT and CT+BT treatments reduced the grape yield but increased the mean cluster weight compared to control vines. BT alone had a little effect on the yield components. Control grapes generally had the lowest soluble solids (&deg;Oe) and highest titratable acidity (g/l). In most cases, control wines had the lowest total phenols, flavan-3-ols, and anthocyanin concentrations, while CT+BT treatment had the highest ones followed by CT treatment. It was concluded that CT+BT produced wines with generally increased total phenols, flavan-3-ols, and anthocyanins, as well as many individual phenolic compounds. Thus, grape yield per vine seems to be strongly connected with the grape and wine compositions. The final cost-effectiveness of this canopy interventions still remains questionable. &nbsp;
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Micke, Warren C., Joseph A. Grant, and James T. Yeager. "Chemical Thinning of `Gala' Apples in California." HortScience 32, no. 3 (1997): 525E—525. http://dx.doi.org/10.21273/hortsci.32.3.525e.
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`Gala', the third most widely planted apple cultivar in California, requires early and precise thinning to produce good fruit size. Thus, chemical thinning would be ideally suited for this cultivar. However, the normally prolonged bloom for apples in California makes timing of chemical thinning applications difficult. In 1995 and 1996 trials, several chemical thinning treatments provided significantly reduced fruit set on `Gala' compared to the untreated control. Three treatments showed promise for commercial use: 1) carbaryl, two applications at petal fall and again at 10-15 mm diameter of the king fruit; 2) carbaryl plus NAD at petal fall; and 3) carbaryl plus 6-benzyladenine and GA4+7 (Accel®), two applications at petal fall and at ≈10 mm diameter of the king fruit. These treatments generally gave reduced fruit set per 100 flower clusters, fruit set per fruiting cluster and/or numbers of fruit removed by follow-up hand-thinning. None of these treatments showed evidence of phytotoxicity, and some increased fruit size over the untreated control.
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Mancha, Luis Alberto, David Uriarte, Esperanza Valdés, Daniel Moreno, and María del Henar Prieto. "Effects of Regulated Deficit Irrigation and Early Cluster Thinning on Production and Quality Parameters in a Vineyard cv. Tempranillo Under Semi-Arid Conditions in Southwestern Spain." Agronomy 11, no. 1 (2020): 34. http://dx.doi.org/10.3390/agronomy11010034.
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The efficient use of water in the vineyard requires knowledge of the crop’s response to irrigation in terms of production and quality and the interaction of the same with the environmental conditions. In this work, the behavior of a trellis system vineyard in cv. Tempranillo, located in the south-west of Spain, was analyzed for three years in relation to different irrigation strategies based on crop evapotranspiration (ETc), and with two levels of crop load established by early cluster thinning. The response of the vineyard to the same irrigation strategy varied depending on the characteristics of the year. The vineyard’s biomass production increased in a linear trend as annual water status improved. However, during pre-veraison, the water status had a more significant impact on the harvest by affecting bud fertility. The increase in individual cluster weight only partially compensated the loss of yield caused by cluster thinning. The year’s characteristics highly conditioned the response to the irrigation treatment and, together with cluster thinning, modified the characteristics of the musts, although the response was varied.
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Zabadal, Thomas J., and Bruce P. Bordelon. "TIMING AND CONCENTRATION OF GIBBERELLIC ACID APPLICATIONS FOR BERRY THINNING AND SIZING OF `VANESSA' SEEDLESS GRAPES." HortScience 28, no. 5 (1993): 570b—570. http://dx.doi.org/10.21273/hortsci.28.5.570b.
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Timing and concentration of GA applications were evaluated for berry thinning and sizing on `Vanessa'. Mid-bloom applications at 0, 5, 10, 15, 20 and 30 ppm GA were tested for berry thinning. Post-bloom applications of 0, 25 and 50 ppm GA at 7, 12, 16 and 21 days past mid-bloom were tested for berry sizing. None of the mid-bloom (thinning) treatments significantly reduced the number of berries per cluster or cluster compactness. Mid-bloom applications at 15, 20 and 30 ppm GA significantly increased berry weight. Post-bloom (berry sizing) treatments significantly increased berry weight with each increase in GA concentration for each time of application. The number of berries per cluster was significantly increased by sizing sprays at 7 and 12 days, but not at 16 or 21 days past mid-bloom. Cluster weight was significantly increased by 25 and 50 ppm GA applied at 7, 12 and 16 days past mid-bloom. All post-bloom applications significantly reduced the number and weight of shot berries.
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Dewhurst, J. P., C. J. Owen, A. N. Fazakerley, and A. Balogh. "Thinning and expansion of the substorm plasma sheet: Cluster PEACE timing analysis." Annales Geophysicae 22, no. 12 (2004): 4165–84. http://dx.doi.org/10.5194/angeo-22-4165-2004.
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Abstract. The storage and subsequent removal of magnetic flux in the magnetotail during a geomagnetic substorm has a dramatic effect on the thickness of the cross-tail plasma sheet. The near-Earth plasma sheet is thought to thin during the growth phase and then rapidly expand after onset of the substorm. The direction of propagation, whether earthward or tailward along the GSM-X direction in the near-Earth tail, may suggest the time ordering of current-disruption and near-Earth reconnection, both of which are key to the substorm process. Cluster's Plasma Electron And Current Experiment (PEACE) allows 4-point observations of electrons at the plasma sheet - lobe boundary as this interface passes over the Cluster tetrahedron. The relative timings of the boundary passage at each spacecraft allow a determination of this boundary's speed and direction of motion, assuming this is planar on the scale of the Cluster separation scale. For those boundaries corresponding to the expansion of the plasma sheet, this direction is fundamental to determining the direction of expansion. We present an example of isolated thinning and expansion of the plasma sheet, as well as a multiple thinning-expansion event that occurs during a more active substorm. Data from the 2001 and 2002 tail passes have been analysed and the average plasma sheet – lobe boundary normal vectors and normal component velocities have been calculated. A total of 77 crossings, typically between 10 and 20 RE downtail, correspond to substorm associated expansion of the plasma sheet over the spacecraft. These had normal vectors predominantly in the GSM-YZ plane and provided no clear evidence for the formation of the near-Earth neutral line occurring before current disruption or vice versa. The expansions of the plasma sheet generally exhibit the appropriate GSM-Z direction expected for the given lobe, and tend to have GSM-Y components that support onset occurring near the origin of the GSM-YZ plane. This result is noteworthy in that it indicates a homogeneous plasma sheet expansion. These expansions have an average velocity along their normal of 60±37kms–1. Conversely we find an average thinning velocity of 43±32kms–1 from 66 substorm-associated thinnings. The normal vectors of the thinning plasma sheet vary considerably in the GSM-YZ plane across the entire magnetotail, suggesting that more complex dynamics govern this process.Key words. Magnetospheric physics (Magnetotail; Plasma sheet; Storms and substorms)bk\\rasphone.
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Guak, Sunghee, Norman E. Looney, and Leslie H. Fuchigami. "296 Chemical Thinning of `Fuji' Apple with Ethephon, NAA, MCPB-ethyl, and Carbaryl." HortScience 34, no. 3 (1999): 493D—493. http://dx.doi.org/10.21273/hortsci.34.3.493d.
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We propose that return flowering of `Fuji' apple can be improved if sufficient flower clusters are removed during or shortly after bloom. In this study conducted at Corvallis, Ore., we evaluated two synthetic auxins, MCPB-ethyl and the Na salt of NAA, each at 0, 4, 8 and 16 ppm, as blossom cluster thinners. Each auxin treatment was applied alone or with 100 ppm ethephon as a tank mix. Six-year-old `Fuji'/M.26 trees were sprayed at full bloom of the king flowers (≈85% of whole-tree full bloom). A follow-up treatment of Sevin XLR (800 ppm carbaryl) was made at 11-mm fruit diameter to determine if carbaryl's known effectiveness as a fruitlet thinner was influenced by the bloom-time auxin or auxin + ethephon treatments. MCPB-ethyl proved ineffective as a bloom-time thinner, whereas the NAA effect on cluster removal was linear with concentration, 16 ppm NAA completely defruiting 33% of initial flower clusters. On control trees fewer than 12% of flowering clusters failed to set fruit. Ethephon alone defruited 25% of the clusters and NAA+ethephon defruited 51% of clusters. It is notable that the NAA and ethephon + NAA treatments did not reduce fruit set on the remaining clusters, resulting in considerable need for hand-thinning. Carbaryl effectively reduced total crop load by increasing the number of defruited clusters and reducing the incidence of doubles and triples. There was evidence to suggest that its effectiveness was compromised by the bloom-time NAA and/or ethephon sprays.